A blow, expected, repeated, falling on a bruise, with no smart or shock of surprise, only a dull and sickening pain and the doubt whether another like it could be borne.

This is how it feels any time a great tragedy is reported from Afghanistan.

One often asks, warily, “Why the hell are we there?”

The deaths of six British servicemen in Helmand last week prompted David Cameron to answer,

We are there to prevent that country from being a safe haven for Al Qaeda, from where they might plan attacks on the United Kingdom or our allies.

Our troops are not only securing the future of the United Kingdom, but also “the future of the world.”

It became difficult to take seriously such grandiloquent rhetoric by the prime minister when, nearly two years ago, he placed an arbitrary deadline on securing the future of the world.

The contradiction is typical of an Afghan policy that Mr Cameron and the Foreign Secretary William Hague have tied up in knots since the summer of 2010. They should cut themselves free from their bonds as this war is not worth the loss of another British life.

David Cameron and William Hague like to think that they are grand strategists who will reverse the drift of the Labour years and prepare the country for the challenges of the twenty-first century.

Perversely, I think one of the tightest knots binding us to Afghanistan was tied by Mr Cameron trying to pursue this ambition. The myopia of his actions prompted a U-turn that overcommitted the United Kingdom to a country of only marginal importance. It has put the Tory leaders in an embarrassing position vis-à-vis withdrawal.

On 25th June 2010, the prime minister announced that our combat troops would be out of the war by 2015.

We cannot be there for another five years having effectively been there for nine years already.

Many pundits saw this deadline and other foreign policy decisions that summer as repeated gaffes. I took a different view; these “gaffes” were part of a deliberate strategy that he and Mr Hague were pursuing at the time, one which I likened to flying a hot air balloon.

They sensed the turbulent winds heading our way this century and believed that the best way to avoid them was to chuck overboard weighty foreign policy commitments in order to make Britain’s balloon soar higher.

It was for this reason that Mr Cameron tried to cool the special relationship with the United States, push away Israel to align closer with Turkey and reset our relations with India at the expense of Pakistan.

Unless we changed our ways, the foreign secretary warned in July, we were set to decline “with all that that means for our influence in world affairs.”

Afghanistan was a commitment that David Cameron and William Hague were unsure about chucking overboard that summer, though the 2015 deadline suggested that they had put it on the edge of the basket.

“By that time we will have been applying ourselves to this [conflict] for 50 percent longer than we applied ourselves to the Second World War,” Mr Hague once remarked, in exasperation.

The deadline was also typical of the caution with which the Tory leaders have sometimes viewed the handling of the war. It came just two days after President Barack Obama dismissed General Stanley McChrystal as the head of allied forces in Afghanistan, reopening a debate about American strategy that many thought had been settled by the president’s West Point speech several months before. Mr Cameron may have felt that this was the last straw.

“We cannot be here for another eight years,” he said during a trip to Helmand in December 2009; the strategy that Obama had laid out that month was “our last big chance for success.”

Had the prime minister and the foreign secretary stuck to this cautious approach, they would have anticipated the Americans’ sudden desire to “rush to the exit,” allowing them to drop the Afghan commitment.

Yet they quickly restored Afghanistan to its original place in the balloon basket and added to its weight in order to play down the strategic significance of the 2015 announcement. In January, David Cameron signed an agreement with President Hamid Karzai of Afghanistan which commits us to furnishing his regime with significant financial and military aid for years to come.

At the press conference, Mr Cameron also made it clear that British combat troops would not leave before 2015, unlike the less dependable French.

The United Kingdom wants “a strong, safe, stable, democratic Afghanistan living in peace and stability with its neighbors.”

Just a few days later, however, the American defense secretary, Leon Panetta, told reporters that America will transition away from a combat role in 2013 and leave in 2014.

The partial U-turn that David Cameron and William Hague made on Afghanistan has now put them in an embarrassing position. If the “primary determinant” of their withdrawal timetable is American policy and if that policy is to “rush to the exit” despite claims to the contrary, Mr Hague and Mr Cameron must join that rush just when they have increased our commitment to the country and raised the world saving stakes of our presence there.

There are many other contradictions in the government’s policy — Al Qaeda is a grave threat to our security yet we will leave Afghanistan in three years’ time whether or not the group is defeated. We are not there to build a perfect society yet ministers often emphasise the progress we have made on development and human rights.

If they truly wish to be great, grand strategists, David Cameron and William Hague should not spend their time in office fiddling with the knots binding them to Afghanistan but cut them altogether. A famous conqueror of that land took a similar approach to knots and he didn’t do too badly…

This story first appeared at Egremont, the official blog of the Tory Reform Group, March 15, 2012.